Enantioselective Total Synthesis of (+)‐Flavisiamine F via Late‐Stage Visible‐Light‐Induced Photochemical Cyclization

The structural features Kopsia alkaloids, in particular multiple all‐carbon quaternary stereocenters in a caged and strained polycyclic skeleton, poses particular challenges for enantioselective total synthesis. Herein, we reported the first total synthesis of (+)‐flavisiamine F. The synthetic approach involved a room‐temperature Overman rearrangement for introducing the chiral amine at C21, a TMS‐promoted ketal Claisen rearrangement for constructing the all‐carbon quaternary stereocenter at C20, and a late‐stage visible‐light‐induced photochemical cyclization for establishing the all‐carbon quaternary stereocenter at C7.     

Multi‐Functional Oxidase Activity of CYP102A1 (P450BM3) in the Oxidation of Quinolines and Tetrahydroquinolines

Tetrahydroquinoline, quinoline, and dihydroquinolinone are common core motifs in drug molecules. Screening of a 48‐variant library of the cytochrome P450 enzyme CYP102A1 (P450BM3), followed by targeted mutagenesis based on mutation‐selectivity correlations from initial hits, has enabled the hydroxylation of substituted tetrahydroquinolines, quinolines, and 3,4‐dihydro‐2‐quinolinones at most positions around the two rings in good to high yields at synthetically relevant scales (1.5 g L^?1 day^?1). Other oxidase activities, such as C?C bond desaturation, aromatization, and C?C bond formation, were also observed. The enzyme variants, with mutations at the key active site residues S72, A82, F87, I263, E267, A328, and A330, provide direct and sustainable routes to oxy‐functionalized derivatives of these building block molecules for synthesis and drug discovery.     

Naturwirkstoffe aus Pflanzen. Biodiversitätsforschung

Due to its deepened natural material research the transdisciplinary biodiversity research offers new options to therapeutical challanges of the 21st century. Besides phytochemicals, known for centuries, these natural materials also include recently known material such as antiviral active high polymer polyphenols of Mediterranean rockroses or new kinds of antiadipos active bitter‐tasting compounds. Natural ressources are invaluable. To protect and preserve these, detailed knowledge of biodiversity on Earth and its embedding in the biogeosystem is required.